Wafer Level Packaging (WLP) is a technology in which a whole wafer is packaged and tested, and then diced into individual chips. The size of a packaged chip is almost the same as that of a bare chip. Wafer Level Chip Size Packaging (WLCSP) technology is totally different from conventional packaging technologies such as Ceramic Leadless Chip Carrier and Organic Leadless Chip Carrier, and satisfies the market requirements for micro-electronic products, e.g., light in weight, small in size, thin in thickness and low in cost. Packaging with the WLCSP technology realizes high miniaturization, and the chip cost decreases significantly with the decrease of the chip size and the increase of the wafer size. The WLCSP technology, which, when being implemented, may take into account the IC design, wafer fabrication and packaging test in combination, is currently a focus in the packaging field and becomes one of the development trends of the packaging technologies.
Fan-out wafer packaging is one kind of WLP. For example, a wafer level fan-out chip packaging method, disclosed in a Chinese invention patent application No. 200910031885.0, includes following process steps: a stripping foil and a film dielectric layer I are sequentially formed on a surface of a wafer of a carrier, and a photoetching pattern opening I is formed on the film dielectric layer I; a metal electrode and a re-wiring metal routing wire which are connected with a base plate end are arranged on the photoetching pattern opening I and a surface thereof, and a film dielectric layer II is formed on a surface of the metal electrode, a surface of the re-wiring metal routing wire, and a surface of the film dielectric layer I which are connected with the base plate end, and a photoetching pattern opening II is formed on the film dielectric layer II; a metal electrode connected with a chip end is arranged on the photoetching pattern opening II; after a chip is arranged on the metal electrode connected with the chip end in an inverting way, the injection molding of packaging material and curing are performed, so as to form a packaging body with plastic-packaging material; the wafer of the carrier and the stripping foil are separated from the packaging body with plastic-packaging material, so as to form a plastic-packaging wafer; a solder ball is reflowed to form a bump; and singulation is performed to form the final structure of the fan-out chip.
Final products packaged and manufactured by the above method only have single-chip functions. To realize whole-system functions, besides a final product, a periphery circuit including all kinds of capacitors, inductors and resistors is required.